BSC 2010 FINAL EXAM QUESTIONS
AND ANSWERS
Why are human sex hormones considered to be lipids? - Answer- They are not soluble
in water.
What does cholesterol have in common with sex hormones? - Answer- Four linked rings
-All steroids have four linked rings.
For good health, you don't want your body to run the LDL part of this diagram faster
than the HDL part because... - Answer- LDL cholesterol is stored; HDL cholesterol is
destroyed.
-If LDL exceeds HDL, your body is probably storing excess cholesterol, which may clog
the arteries and cause heart disease.
The sex hormones estradiol and testosterone belong to which class of molecules? -
Answer- Lipids
-Steroids, such as estradiol and testosterone, are lipids based on their insolubility in
water. The molecules are characterized by a carbon skeleton consisting of four fused
rings of carbon atoms.
High cholesterol levels are considered a major risk factor for heart disease. If it is so
bad for humans, why does the body make cholesterol in the first place? - Answer-
Cholesterol is the precursor for many important molecules such as sex hormones.
- Cholesterol is the basis for many steroid molecules, including sex hormones.
The element present in all organic molecules is___. - Answer- Carbon
The large diversity of shapes of biological molecules is possible because of the
extensive presence of ____ in the molecules. - Answer- Carbon
- With four electrons to share, carbon-based molecules can be multi branching and 3D
variable.
How many electron pairs does carbon share in order to complete its valence shell. -
Answer- 4
Why are hydrocarbons insoluble in water? - Answer- The majority of their bonds are
non-polar covalent carbon-to-hydrogen linkages.
Which of the following is a hydrocarbon? - Answer- C3H8
, -This is a typical hydrocarbon with single covalent bonds; the number of hydrogen
atoms is equal to two times the number of carbon atoms plus 2.
Molecules that have the same chemical formula (same numbers of each atom) but
different 3D shapes are called_____. - Answer- isomers
-Isomers of carbon compounds can arise in several different ways.
How do isomers differ from one another? - Answer- Isomers differ in the arrangement or
bonding of atoms.
-Isomers may differ in the covalent arrangements of their atoms or the position of
double bonds within the molecule and thus have different chemical properties.
Which of the following best describes cis-trans isomers? - Answer- They differ in their
spatial arrangement around inflexible double bonds.
-Cis-trans isomers maintain the same covalent partnerships, but the atoms may be
arranged differently.
Variations in the reactive properties of different organic molecules are most closely
associated with_____. - Answer- The presence or absence of functional groups.
-Functional groups are the most common participants in chemical reactions.
Citric acid makes lemons taste sour. Which of the following is a functional group that
would cause a molecule such as citric acid to be acidic? - Answer- Carboxyl
-The carboxyl group can release a hydrogen ion when in solution.
Which statement about a methyl functional group is correct? - Answer- A methyl group
consists of a carbon bonded to three hydrogen atoms.
-A methyl group consists of a carbon covalently bonded to three hydrogen atoms.
Most organic compounds contain carbon and ____. - Answer- Hydrogen
-In fact, some argue that carbon dioxide should not be considered an organic molecule
because it does not contain hydrogen.
Organic chemistry is currently defined as - Answer- The study of carbon compounds.
Vitalism gave way to mechanism, the view that____. - Answer- Physical and chemical
laws govern living systems.
-Living things are subject to physical and chemical laws. They so not exist outside of
them.
What are the six most important chemical elements of life? - Answer- Carbon, nitrogen,
oxygen, hydrogen, phosphate, sulfur.
-All of these elements are capable of forming strong covalent bonds, important in
building large, complex molecules.
Which of the following is an organic molecule? - Answer- CH4
AND ANSWERS
Why are human sex hormones considered to be lipids? - Answer- They are not soluble
in water.
What does cholesterol have in common with sex hormones? - Answer- Four linked rings
-All steroids have four linked rings.
For good health, you don't want your body to run the LDL part of this diagram faster
than the HDL part because... - Answer- LDL cholesterol is stored; HDL cholesterol is
destroyed.
-If LDL exceeds HDL, your body is probably storing excess cholesterol, which may clog
the arteries and cause heart disease.
The sex hormones estradiol and testosterone belong to which class of molecules? -
Answer- Lipids
-Steroids, such as estradiol and testosterone, are lipids based on their insolubility in
water. The molecules are characterized by a carbon skeleton consisting of four fused
rings of carbon atoms.
High cholesterol levels are considered a major risk factor for heart disease. If it is so
bad for humans, why does the body make cholesterol in the first place? - Answer-
Cholesterol is the precursor for many important molecules such as sex hormones.
- Cholesterol is the basis for many steroid molecules, including sex hormones.
The element present in all organic molecules is___. - Answer- Carbon
The large diversity of shapes of biological molecules is possible because of the
extensive presence of ____ in the molecules. - Answer- Carbon
- With four electrons to share, carbon-based molecules can be multi branching and 3D
variable.
How many electron pairs does carbon share in order to complete its valence shell. -
Answer- 4
Why are hydrocarbons insoluble in water? - Answer- The majority of their bonds are
non-polar covalent carbon-to-hydrogen linkages.
Which of the following is a hydrocarbon? - Answer- C3H8
, -This is a typical hydrocarbon with single covalent bonds; the number of hydrogen
atoms is equal to two times the number of carbon atoms plus 2.
Molecules that have the same chemical formula (same numbers of each atom) but
different 3D shapes are called_____. - Answer- isomers
-Isomers of carbon compounds can arise in several different ways.
How do isomers differ from one another? - Answer- Isomers differ in the arrangement or
bonding of atoms.
-Isomers may differ in the covalent arrangements of their atoms or the position of
double bonds within the molecule and thus have different chemical properties.
Which of the following best describes cis-trans isomers? - Answer- They differ in their
spatial arrangement around inflexible double bonds.
-Cis-trans isomers maintain the same covalent partnerships, but the atoms may be
arranged differently.
Variations in the reactive properties of different organic molecules are most closely
associated with_____. - Answer- The presence or absence of functional groups.
-Functional groups are the most common participants in chemical reactions.
Citric acid makes lemons taste sour. Which of the following is a functional group that
would cause a molecule such as citric acid to be acidic? - Answer- Carboxyl
-The carboxyl group can release a hydrogen ion when in solution.
Which statement about a methyl functional group is correct? - Answer- A methyl group
consists of a carbon bonded to three hydrogen atoms.
-A methyl group consists of a carbon covalently bonded to three hydrogen atoms.
Most organic compounds contain carbon and ____. - Answer- Hydrogen
-In fact, some argue that carbon dioxide should not be considered an organic molecule
because it does not contain hydrogen.
Organic chemistry is currently defined as - Answer- The study of carbon compounds.
Vitalism gave way to mechanism, the view that____. - Answer- Physical and chemical
laws govern living systems.
-Living things are subject to physical and chemical laws. They so not exist outside of
them.
What are the six most important chemical elements of life? - Answer- Carbon, nitrogen,
oxygen, hydrogen, phosphate, sulfur.
-All of these elements are capable of forming strong covalent bonds, important in
building large, complex molecules.
Which of the following is an organic molecule? - Answer- CH4
